Ring hammer mill



Jan. 10, 193$ s. D. HARTSHORN 2,143,063

' RING HAMMER MILL Filed July 17, 1956 5 Sheets-Shet 1 S. D. HARTSHORN Janfi 6,1939.

' RING HAMMER MILL Filed July 17, 1 936 5 Sheets-Sheet 2 NVENTOR )Ml Jan. 10, 1939. D HARTSH N 2,143,068

RING HAMMER MILL Filed July 17, 1936 5 Sheets-Sheet 3 ATTORNEYS k g wzadm Jan. 10, 1939.

s. D. HARTSHORN 2,143,068

RING HAMMER MILL Filed July 17, 1936 S-Sheets-Sheet 4 z I )NVENTOIRY I PM ATTORNEYS Jan. 10, 1939.

S. D. HARTSHORN RING HAMMER MILL Filed July 1'7, 1936 ATTO RI T YS 5 Sheets-Sheet 5 The hammer mechanism comprises a number of flanges 39 regularly spaced along the shaft. within the cage, by spacer collars 40'. The last flange abuts against the collar 4| which is integral with the shaft. The assembly of the flanges 39 and spacer collars 40 is held tightly in position against collar 4i by suitable means at the opposite end, such as a nut (not shown).

A set of suspension rods '42 and a set of pusher rods 43 extend longitudinally through suitable holes in the flanges 38 at regularly spaced intervals around the circumference of these flanges, and are fastened in place in a suitable manner. The diameter of the circle of pusher-rods 43 is somewhat greater than that of the circle of suspension rods 42, but each rod 43 is located quite close to its associated rod 42. Ring hammers 44 are placed over each adjacent pair of rods 42 and 43 within the spaces between the adjacent flanses 38.

In operation, the hammer shaft 30 is rotated by an external source of power (not shown). When shaft ".is rotating the rings 44 fly outwardly due to centrifugal force into the positions illustrated. Each rod 43 is so situated that it Just touches the inner periphery 45 of its associated ring when the radius 1 through the center of shaft and of rod 42 coincides with the diameter of the ring. Under this condition, the rods 42 bear substantially all of the centrifugal force of their respective rings. Pusher rods 43 bear no appreciable force until the rings are resisted by material in the cage, in which case they serve to push the rings in their direction of motion. In this embodiment rod 43 touches the ring at a point about 90 from the point of contact with rod 42; although the 90 spacing is not essential.

The material to be broken is fed through the feed chute into the cage. The rotation of the hammer shaft causes the ring hammers 44 to extend out radially into the position shown so that they strike masses of the material which have dropped from the chute, crushing them against breaker plate l2 and the cage section ii, thereby breaking up the material. Those pieces of the material which are broken small enough pass through the spaces 20 between the screen bars and drop into a suitable receptacle below. Unbreakable material such as tramp iron is carried around and thrown into the pocket I! from where it is removed from time to time.

Since the tramp iron pocket is at the left in Fig. 1, the direction of rotation of the shaft must be clockwise with reference to this figure.

The movable screening.section Ii is susceptible of adjustment to regulate the distance between the screen bars and the rotating hammers. To move the cage section closer to the hammers, it is only necessary to turn crank 28 to rotate lever arm 23 upward. By this device compensation for wear or a desirable adjustment for producing a satisfactorybreaking operation may be obtained.

Figs. 3 and 4 show a comparison of the crushing action of the double support system of Figs. 1 and 2 and a single support system, the double system being illustrated in Fig. 3 and the single system in Fig. 4. As these figures give a general example the rods 42 and 43 are not shown exactly 90 apart around the inner periphery of the ring. In Fig. 3 the ring 44 is shown after striking a mass 46 of the material, which is compressed and crushed between the ring and the screen bars. Under this condition the ring is being pushed in its direction of rotation by the pusher bar 43-. If the material offers great resistance the ring may be lifted from the normal position shown at dotted line 44a, out of contactwith the suspension bar 42, as shown. If any such lifting occurs the original perpendicular'diameter d of the ring swings back through an angle u to the position D. The centrifugal force exists along the line through the centers of shaft 30 and of the ring 44, which coincides with diameter D, and is represented by the vector a. The pushing or driving force due to pusher bar 43 is along the line through the center of ring 44 and the point of contact of the pusher bar with the inner surface of, the ring, and is represented by vector -b. The total crushing component of force is the vector difference of vectors a and b, and is represented by the .vector c. The net radial crushing pressure is represented by the vector f.

In the case of the single support of the hammer ring (Fig. 4), the ring must always swing back at least some distance upon striking material inorder to overcome the resistance of the material, and for a given degree of resistance the angle 11. is greater than in the case of double support. The

centrifugal force a; is directed along diameter D and is of the same magnitude as in Fig. 3; but diameter D in Fig. 4 is swung further back than in Fig. 3. The component of force on the suspension bar is then represented by vector 42;, and the total crushing force on the material by the vector 01. The resultant radial crushing pressure is therefore the vector ii. The advantage of the double support is immediately apparent since vectors e and f are both considerably larger than vectors 0; and ii. To develop a given crushing force, then, the machine can be driven slower in the case of the double support.

Fig. 5 illustrates a modification of the ring hammer which develops greater crushing force than the rings 44, for a given speed of rotation. In Fig. 5 the ring 48 is almost solid and is provided with a heart-shaped opening 49 for receiv-- ing the bars 42 and 43. The shape of the heart Each of these rings is suspended on a cam-shaped supporting member 50 fastened on rods 5|, and having a T-bead 501 extending over the periphcry of the'adjacent flanges 39. The members 50 provide arcuate supporting surfaces which support a considerable extent of the inner periphery surface of the rings. The ring supporting surfaces of members 50 are such that the inner ring peripheries just make contact therewith when the rings extend out radially in the normal direction of the centrifugal force.

When the rings strike masses of the material the members 50 act similarly to the two point supports previously described, and perform the functions of the suspension and pusher supports; and the rings may be lifted to the position shown by the dotted lines 44a when resisted by the material. This arrangement has good wearing properties because of the large supporting surfaces for the rings. Furthermore, owing to the presence of portions 501, the flanges 39 may be arsaoee Fig. 1 so that greater space is left for the material being crushed.'

Fig. 7 illustrates another modification in which the ring hammers 53, mounted on two bars, I3 and p 51, are approximatelytriangular. The rounded triangular shape results in a somewhat greater net radial crushing pressure inasmuch as thecenter of gravity is farther from the pivot when the ring is supported at one of its corners. The net radial crushing pressure is practically equal to ,the centrifugal force. It might be possible to use squares instead of triangles.

In Fig. 8 a single large round triangular shaped hammer ring 63 is used between a pair of flanges 33. These large rings are driven .by cam shaped supporting members 8], somewhat similar to members 50 in Fig. 6, fastened to the hammer shaft 30. Members 6! have arcuate surfaces which conform with the shape of, and contact with, the inner surfaces of ring hammers 60 when extending radially outward in the normal direc# tion of the centrifugal force.

This arrangement, like that of Fig. 6, is in eifect another form ofthe two point support; and when the hammer rings strike. masses of the material they may be raised somewhat from the suspension members Si in the manner shown by dotted lines 60a.

In this form' of crushing mill the several large ring hammers positioned along the shaft are pref erably given different positionsaround the circumference so that the crushing resistance on the machine is substantially uniform. Two other of these large rings are shown at 631 and 602. With this arrangement a large ring may be used even though the machine is relatively small.

Fig. 9 shows a somewhat different ring hammer and manner of attachment. The ring 65 is suspended on the shaft 30 and is pushed by the pusher bar 66 suitably fastened to flange 33. To prevent the ring from slipping around during operation the inner periphery thereof is scalloped as shown at 61. Slipping can also be minimized by making the ring in a rounded triangular form as shown at 10, in Fig. 10.

Any desired number of rings of the form 65 or 10 may be used in the same hammermill spaced "I between flanges along the shaft, although only two are shown; and the rings may be placed in a spaced angular positions around the shaft. when the rings are angularly spaced at intervals around the shaft the pusher bars 33 cannot be extended through all of the flanges 33, because of interference with the rings. The bars are therefore'of the stub type extending between the two flanges containing the individual rings.

Hammer rings constructed and arranged according to Figs. 9 or ,10 are advantageous for use in small mills. The relatively large hammers suspended on the main shaft 33 provide sufficient weight to developa satisfactory crushing force.

Fig. 11 shows an arrangement of the ring hammerswhich avoids stubbing the suspension bars,

Instead of individual sus- 36 in Figs.-9 and 10. pension bars 33 within each individual ring, there is provided an individual cam 13 keyed to the shaft 30. Individual rings 11 are placed over the individual cams 13 between two adjacent flanges 33. Any number of these rings may be placed along the shaft, and they may be situated at different angular positions around the shaft as shown by ring 13.

.. .Fig. 12 shows a ring suspension arrangement in which the normal direction of the centrifugal force causes the ring to contact only a suspension bar, but not a pusher bar. This arrangement is applicable to a hammermiil such as that shown in Figs. 1 and 2. In this arrangement is shown in contact with the suspension bar 42; but the pusher bar 43 is located within the hammer ring and out of contact with the. inner periphery th'ereof. In this case the ring engages the pusher bar only after striking the material.

This idea of maintaining a pusher bar or surface'normally out of contact with the ring may be used. if desired. in other embodiments of this invention, such as those shown in Figs. 5 to 7.

The principle of the ring hammers may, if desired, be applied to impact hammers. Fig. 13 iilustrates an impact hammer 30 fastened to a shank in the form of a ring 3! having a protruding tongue 82 carrying a pivot pin 33 to which the hammer is attached. The ring is hung over suspension rod 42 and pusher rod 43 as in the case of Fig. l. The rod 43 is preferably located about one-third the distance from the suspender bar 42 to the striking surface of the hammer. A pusher casting such as 50 in Fig. 6 could, of course, be substituted for the rods 42 and 43.

It is possible for the rings of Fig. 13 to rotate without lifting away from rod 42 when the hammer strikes masses of material. This kind of retation can be prevented, if desired, by scalloping the inside of the ring as shown in'Fig. 9, or by using triangular ring shanks with suspension and pushing arrangements such as those shown in Figs. '7, 8 or 10, or the heart shape as in Fig. 5. Fig. 14 is an example of an impact hammer pivoted to the tongue of a large triangular rin 84 somewhat similar to ring 60 of Fig. 8, suspended on a cam-shaped member 3! I Another expedient would be positively to pivot the ring shank to rod 43 as shown in Fig. 15, wherein there is provided a lip 35 having a hole which fits over the rod. When the material offers heavy resistance to the hammer the ring can pivot on rod 43 and lift away from rod 42.

' Inasmuch as the supported rings act very similarly whether used as hammers themselves or simply as hammer shanks, the term "hammer ring is usedin the specification to cover both cases.

It may sometimes be desirable to serrate the outer surfaces of the ring hammers. The serrations may. take the form of spaced teeth 36 as shown in Fig. 16. Theseserve to draw the material more quickly into the machine, reducing slippage, and further, to disintegrate foreign material such as wood, gunny sacks, etc.

Fig. 1'! illustrates an alternative form .for the toothed serrations in which only the leading tooth surfaces 31 are perpendicular'to the Cll'Cllll'lfel'-.

ence.

serrations are not limited to use on circular ringhammers, but may be used also on other types such as the triangular.

I claim:

1. A hammermiil comprising a rotary hammer system including annular hammers and means for individually supporting and propelling each hammer, said means including a propulsion element internally engaging the hammer at a forward point with respect to the direction of movement of the hammer, and a suspension element in position to engage the hammer internally at a point which is rearward and inward ofsaid pro-- pulsion engagement with respect to said direction of movement of the hammer and which is to re' ceive the centrifugal thrust on the hammer dur ing idling rotation of'the hammer system, the hammer being mounted for movement inwardly the ring 44 suspension element upon crushing engagement with material to transfer the centrifugal thrust about the propulsion element and away from the of the hammer from the suspension elementto the material; and a cooperating crushing c ber including a crushing wall extending along the hammer path arranged to hold material in position for crushing by the hammers.

2. A hammermill as set forth in claim 1 in which the hammer is provided with a central opening and the propulsion element and suspension element are located in the opening.

3. A hammermillas set forth in claim 1 in which the suspension element is positioned at an angular distance of the order of 90 from the propulsion element about the center of the hammer when in engagement with both elements, arranged to exert substantially the full centrifugal thrust of the hammer against the material when the hammer is moved inwardly away from the.

suspension element upon crushing engagement with material.

4. A hammermili as set forth in claim 1 in which each hammer is substantially a solid disc cut away to receive the propulsion element and the suspension element.

5. A hammermilias set forth in claim 1 in which the hammer is provided with a central opening with a peripheraisymmetrical series of depressions having the same spacing as the sus- CERTIFICATE Patent No. 2,115,068.

STANLEY BENTON HARTSHORN.

being suitably spaced to constitute 'l. A hammerm'ill as set-forth in claim'l in which the suspension element is on the opposite side of the shaft'axis with relation to the propulsion element.

8. A hammermill comprising a crushing chamber the walls of which comprise a screening cage, a hammer ring situated within said cage and adapted to be carried by a rotating shaft, said ring being supported at more than a single supporting point, a first supporting point being 10- cated at a further radial distance from said shaft her, said ring being supported by more than a single supporting element, a first supporting element being located at a further radial distance from said shaft and being further forward in the direction of rotation than a second supporting element, whereby said ring is pushed in its path of motion at said first element when said ring wedges material to be crushed against a-wall of said chamber, said ring'being formed as a disk which is solid except for a heart-shaped opening through which a support of each of said supporting points protrudes, the lobes of said opening pivot seats for said supports. 7

sum nnn'rou nanrsnonn.

OF CORREC'IIQN.

January 10, 1959 It is hereby certified that error appears in the printed specificationoft he above numbered patent requiring correction as follows: Rage li -first column, line claim 1, strike out the words, -"about the propulsion 'ele ment and away from the" and insert the same before suspension, line 1, same claim; and that the said- Letters Patent shouldberead with thi's col:- .rec tion therein that the same may conformto the record of the case in the Patent Office.

Signed and :sealed this 7th day Osman, A.D. 19 9.

(Seal) Henry Van Arsdale'.

Acting Commissioner of Patents. 

